Implement Retry pattern with exponential backoff

[awesomefei]

In practice, we often retry with exponential backoff to avoid making traffic congestion/server load worse, would be nice to implement this option.

Also, I would like to implement this.

[iluwatar]

Yes, I agree. Go ahead @awesomefei

[AnaghaSasikumar]

Hi, is this done?

[AnaghaSasikumar]

Created pull request #797 in case it's still needed. I am new to open source, would really appreciate any feedback. I used this source to do it: https://cloud.google.com/storage/docs/exponential-backoff
Updated: #829